/*
 * Copyright 2020 Google LLC. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.mlkit.vision.demo.barcodescanner;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;

import com.google.mlkit.vision.barcode.Barcode;
import com.google.mlkit.vision.demo.GraphicOverlay;
import com.google.mlkit.vision.demo.GraphicOverlay.Graphic;

/**
 * Graphic instance for rendering Barcode position and content information in an overlay view.
 */
public class BarcodeGraphic extends Graphic {

    private static final int TEXT_COLOR = Color.BLACK;
    private static final int MARKER_COLOR = Color.WHITE;
    private static final float TEXT_SIZE = 54.0f;
    private static final float STROKE_WIDTH = 4.0f;

    private final Paint rectPaint;
    private final Paint barcodePaint;
    private final Barcode barcode;
    private final Paint labelPaint;

    BarcodeGraphic(GraphicOverlay overlay, Barcode barcode) {
        super(overlay);

        this.barcode = barcode;

        rectPaint = new Paint();
        rectPaint.setColor(MARKER_COLOR);
        rectPaint.setStyle(Paint.Style.STROKE);
        rectPaint.setStrokeWidth(STROKE_WIDTH);

        barcodePaint = new Paint();
        barcodePaint.setColor(TEXT_COLOR);
        barcodePaint.setTextSize(TEXT_SIZE);

        labelPaint = new Paint();
        labelPaint.setColor(MARKER_COLOR);
        labelPaint.setStyle(Paint.Style.FILL);
    }

    /**
     * Draws the barcode block annotations for position, size, and raw value on the supplied canvas.
     */
    @Override
    public void draw(Canvas canvas) {
        if (barcode == null) {
            throw new IllegalStateException("Attempting to draw a null barcode.");
        }

        // Draws the bounding box around the BarcodeBlock.
        RectF rect = new RectF(barcode.getBoundingBox());
        rect.left = translateX(rect.left);
        rect.top = translateY(rect.top);
        rect.right = translateX(rect.right);
        rect.bottom = translateY(rect.bottom);
        canvas.drawRect(rect, rectPaint);

        // Draws other object info.
        float lineHeight = TEXT_SIZE + (2 * STROKE_WIDTH);
        float textWidth = barcodePaint.measureText(barcode.getRawValue());
        float left = isImageFlipped() ? rect.right : rect.left;
        canvas.drawRect(
                left - STROKE_WIDTH,
                rect.top - lineHeight,
                left + textWidth + (2 * STROKE_WIDTH),
                rect.top,
                labelPaint);
        //Renders the barcode at the bottom of the box.
        canvas.drawText(barcode.getRawValue(), left, rect.top - STROKE_WIDTH, barcodePaint);
    }
}
